Ok, to follow up with some reflections.
No one in their right mind would go from Europe to Yangshuo just for sport climbing, but I knew/suspected that much before going. A visa sets you back about €160, and closer to €250 if you like me have to fly to a visa center to hand over a bunch of docs and take some fingerprints. This is not including the opportunity cost for filling in the paper work (which should be approximately 8-10 hours times your hourly salary less the marginal tax, taking the cost of obtaining a visa to well north of € 300.) Adding the cost of getting there and I could get to and stay at way better climbing areas around the Mediterranean basin for a few months for the same cost. Otoh, for the price, the restaurant food is better at Yangshuo than at any other climbing area in the world except Greece (and quite likely Turkey/Syria/Libanon, but I have not been.)
To get to the climbing areas you more-or-less have to drive on a scooter which strikes me as insanely dangerous. If I was that willing to risk my life I would have a much better alpine CV. I am wearing a helmet when doing alpine rock routes at least.
Visiting china for other reasons that climbing might make total sense of course, and the main part of our trip was general tourism/sight-seeing. The food is amazing, some of the sights are very interesting, and thanks to my wife's contacts we could visit some factories, talk to people in business and academicians etc.
For climbing I agree with m.cooke.1421 about Lei Pi Shan. For us it was by far the best sector, and the only sector we revisited a second time. "Dream and Hope" 7c+ was the stand-out route of the ones I tried: very onsight friendly as well, but make someone else hang in the draws if possible. The sector is fairly crowded of course, and there are not many routes, not more than for a few days unless getting stuck in with a multi-day project.
We went to White Mountain the first day, but maybe because it was less overcast than promised, it did not live up to its reputation. I did the three classic 7bs (Yangshuo Hotel, China White and Phoenix) and flailed on the classic 7c (White devil) and was generally underwhelmed by the quality.
Riverside was better than White Mountain to me, but really painful with a road so close behind. You have to like slapping for jugs though, and for my wife who's a more refined taste it's an uninteresting sector.
The second best sector was Dragon city, which had by far the best rock of all sectors. Quite similar in style to Siurana, and apparently almost always deserted. The sector requires a cold overcast day though as it has a pure south-facing aspect. The stand-out routes among those I did was Angry Bird 7b and Double Dragon 7b+ (very sharp pocket, make sure that you have a decent margin on mid 7s.)
We also went to the Egg, which was OK for 6s. They are building an enormous apartment complex which should be able to host tens of thousands of people just in front of it though, so be prepared for noise...
Moon Hill is closed, likely for good.
The guidebook Yangshuo Rock - A China Climbing Guide is extremely expensive and has a lot of pages. Luckily it was out of print so the hotel let us borrow their copy. I don't think I used a worse guidebook, which says a lot since I live in France. Each climb has a (very) wordy description of immature shenanigans the guidebook writer and his homies was up to at the time of climbing/trying the route. Don't expect it to have useful info like what features the climb follows.
We stayed in "Climbers Inn" in Yangshuo which is the best hotel I've stayed in for climbing. Very simple rooms but with a 5 star service from the hosts at a 1 star price. I cannot recommend it enough.
